1. Field of the Invention
The present invention relates to an image forming system, an image forming apparatus, a control method therefor, and a program implementing the control method, and more particularly to an image forming system and an image forming apparatus, which are capable of storing document data once having been printed, and when the document data is to be copied, performing a copy process using the stored document data without executing optical image reading of a print sheet subjected to the print process, as well as to a control method therefor and a program implementing the control method.
2. Description of the Related Art
Conventionally, there has been proposed an image forming apparatus, such as a multi-function printer, which stores document data in a server apparatus after having printed out the same, in association with a sheet identifier recorded on a print sheet subjected to the print process, and when the document data is to be copied, determines the original document data by reading the sheet identifier recorded on the print sheet without executing optical image reading of the printed print sheet, and then acquires the document data from the server apparatus for printout (see e.g. Japanese Laid-Open Patent Publication (Kokai) No. H10-308868).
In an image forming apparatus of this kind, in the case of copying document data once having been printed, the copy process is performed using stored document data without using optically read image data, which makes it possible not only to avoid degradation of image quality, but also to achieve a quick copy process. The copy process described above will be hereinafter referred to as “i-copy” throughout the present specification.
However, the conventional i-copy function suffers from the problem that when a print sheet printed with document data and having a sheet identifier recorded thereon happens to be lost and pass to a third party, for example, unauthorized i-copy might be easily carried out by the third party, and therefore high security in the i-copy function cannot be ensured.